1. Field of the Invention
The present invention relates to a three-dimensional display station and method for enabling an observer to observe 3-D images by projecting parallax images to both eyes of the observer. The present invention particularly relates to a three-dimensional (hereinafter, this is referred to as "3-D") display station and method for enabling observers to observe 3-D images around a display screen horizontally arranged.
2. Description of the Related Art
Recently, owing to progress in liquid-crystal display ("LCD") technology, CRT technology, and the like, high resolution display stations and high density display stations have been developed. On the other hand, owing to faster CPUs, generation speed of images has also speeded up. Due to this progress, it becomes possible rapidly to generate images using parallaxes of both eyes, left and right eyes, as well as flat images. For this reason, it becomes possible to display images in three dimensions, and to grasp objects in a virtual space without using real ones. These 3-D displays can be widely applied to reference of the same objects by many persons in teleconference systems, arcade games, 3-D display of computer-aided design ("CAD") information in the CAD fields, transportation control of airplanes and the like, simulators for experiments and the like.
Using known technologies presently developed into 3-D TVs, there are TVs using eye glasses, TVs using parallax barriers, stereogram-type TVs, and the like. FIG. 1 shows a known 3-D TV using a lenticular lens. By vertically arranging a display unit 300 and defining the region opposing to a display screen of the display unit 300 as a 3-D visible range 302, an observer 304 can observe a 3-D image within this range by seeing different images having parallax between left and right eyes. FIG. 2 is a top view of FIG. 1. The 3-D visible range is a range of width determined by the pupillary distance 312 of the observer 304. The display unit 300 is composed of an LCD panel 306, a shutter 308, and a lenticular lens 310 for projection. On the LCD panel 306, parallax images for a right eye and parallax images for a left eye are displayed alternately at a frame period of, for example, 1/60 sec at positions different by a pixel. The parallax images for a right eye on the LCD panel 306 are projected to the direction of the right eye of the observer 304, as shown by full lines, through openings of a slit 308 corresponding to respective pixels. In addition, the parallax images for a left eye, having positions different from the parallax images for a right eye respectively by a pixel, are projected in the direction of the left eye of the observer 304, as shown by broken lines, through openings of a slit 308 corresponding to respective pixels. Consequently, the observer 304 recognizes the 3-D images by observing images having parallax between left and right eyes. Thus, known 3-D display stations realize 3-D perception in the front direction, relative to an axis normal to the display screen, by selecting images more necessary for human eyes among display light of images projected from the display screen to its front and using parallax of the images between the right and left eyes.
However, in such known 3-D display stations, the display unit 300 should be installed facing the eyes of the observer 304 , and the range where 3-D images can be recognized is limited to the 3-D visible range 302 that is in front of the display unit 300. Therefore, a problem arises when many persons want to observe the same objects in teleconference systems, arcade games, 3-D display of CAD information in the CAD fields, transportation control of airplanes and the like, simulators for experiments and the like, because such observation by many at once cannot be performed. In addition, if many persons observe an image, in a usual display station, a display unit may be horizontally arranged. However, if the display unit 300 of the known 3-D display station are horizontally arranged, a 3-D visible range 302 is located on the display unit 300, and hence, it is irrational that observers exist in such positions.